High temperature thermal stability investigations of ammonium sulphide passivated InGaAs and interface formation with Al_2O_3 studied by synchrotron radiation based photoemission

摘要

High resolution synchrotron radiation core level photoemission measurements have been used to undertake a comparative study of the high temperature thermal stability of the ammonium sulphide passivated InGaAs surface and the same surface following the atomic layer deposition (ALD) of an ultrathin (～1 nm) Al_2O_3 layer. The solution based ex situ sulphur passivation was found to be effective at removing a significant amount of the native oxides and protecting the surface against re-oxidation upon air exposure. The residual interfacial oxides which form between sulphur passivated InGaAs and the ultrathin Al_2O_3 layer can be substantially removed at high temperature (up to 700 ℃) without impacting on the InGaAs stoi-chiometry while significant loss of indium was recorded at this temperature on the uncovered sulphur passivated InGaAs surface.